Spectroscopy

Abstract

A graphite electrode for use in spectroscopic analysis in which at least the region of the electrode intended for contact with the material to be analyzed has a layer comprising the heat reaction product of graphite with a salt of a refractory metal and a salt of an alkali earth metal.

I claim: 
     
       1. A graphite electrode for use in spectrospopic analysis in which at least the region of the electrode intended for contact with the material to be analysed has a layer comprising the heat reaction product of graphite with a salt of a refractory metal selected from the group consisting of zirconium vanadium, molybdenum, and lanthanum and a salt of an alkali earth metal. 
     
     
       2. A graphite electrode as claimed in claim 1 wherein the reaction product includes a carbide/nitride of the refractory metal. 
     
     
       3. A graphite electrode as claimed in claim 1 wherein the alkali earth metal is calcium or magnesium. 
     
     
       4. A graphite electrode as claimed in claim 3 wherein the salt of the alkali earth metal is a metal nitrate. 
     
     
       5. A graphite electrode as claimed in claim 4 wherein the salt is calcium nitrate. 
     
     
       6. A graphite electrode as claimed in claim 5 wherein the calcium nitrate is in the form of calcium carbonate in nitric acid. 
     
     
       7. A graphite electrode as claimed in claim 6, wherein the salt of the refractory metal is a metal nitrate. 
     
     
       8. A graphite electrode as claimed in claim 7 wherein the salt is zirconium nitrate. 
     
     
       9. A method for producing a graphite electrode for spectroscopic analysis comprising treating at least the region of the electrode intended for contact with the material to be analysed with the salt of a refractory metal selected from the group consisting of zirconium, vanadium, molybdenum and lanthanum and the salt of an alkali earth metal and heating the treated graphite to a temperature producing a reaction with the salt. 
     
     
       10. A method as claimed in claim 9 wherein the heating is in an inert ambient. 
     
     
       11. A method as claimed in claim 10 wherein the ambient contains a reducing component. 
     
     
       12. A method as claimed in claim 9 wherein heating is by electric current through the graphite. 
     
     
       13. A method as claimed in claim 9 wherein the salt of the refractory metal is a metal nitrate. 
     
     
       14. A method as claimed in claim 9 wherein the alkali earth metal is selected from the group including calcium and magnesium. 
     
     
       15. A method as claimed in claim 14 wherein the salt of the alkali earth metal is a metal nitrate. 
     
     
       16. A graphite electrode when produced by the method of claim 9.